Unfortunately the way your windows were installed will limit what treatments you can use. You are going to have to use something that is mounted outside and above the windows. You can do cellular shades, wood blinds, roller blinds or plantation shutters. You could also use stationary drapery panels at each end to add color and softness to the space.

As far as what is ideal, that is pretty subjective! Many people love plantation shutters, but I find them claustrophobic. I like to have my windows completely open, unless I need some sun control or privacy at night. I like to use cellular shades with drapes.

I'll preface this by saying that my house is a ranch with many mid-century modern touches but also traditional aspects such as 6-panel doors. Our furniture is mainly MCM. I love our house, but am surprised by how often people spontaneously say what a nice house it is. Hence, my comments on how I appreciate our "dated" window coverings:

First, I enjoy my mini-blinds in my office and living room. Both have bow windows. We can look out, but don't feel exposed. These are 6 foot windows about a foot above the floor. In the living room I have sheer draperies that I close at night.

In our dining area on the back of the house we have 24 feet of windows/a sliding door that all go to the floor. On those I have vertical blinds (how dated!) that the previous owners installed. They have vertical lines so when closed they look like striped draperies. When tilted open I don't feel exposed but can see the garden in the back. For temperature control we also have honeycomb blinds that we pull down only on days with extreme heat or nights with extreme cold.

you could do a woven wood blind for the window

or a cellular

Actually drapery would be fine in this room because you could do identical treatments on all three openings. It would just be a little tight on the raised bar side.